Tuning the charge states in InAs/GaSb or InAs/GaInSb composite quantum wells by persistent photoconductivity

Abstract

We have experimentally studied the persistent photoconductivity (PPC) in inverted InAs/GaSb and InAs/GaInSb quantum wells, which can be tuned into a bulk-insulating state by electron-hole hybridization. Specifically we tune the bulk band structure and carriers with light-emitting diode (LED) illuminations. The persistent photoconductivity could be negative or positive, depending on the specific doping structure and the illuminating photon energy. Compared to the widely-used electro-statically gating method, our findings provide a more flexible and non-invasive way to control the band structures and charge states in InAs/GaSb and InAs/GaInSb quantum wells (QWs).

Optical tuning of the charge carrier type in the topological regime of InAs/GaSb quantum wells

“…This process leads to the depletion of electrons in the InAs quantum well, in analogy to the electric-field tuning via a negative front gate. This negative persistent photoconductivity has been also shown for GaSb/InAs films recently [41]. For lower photon energies, this process is absent (see Ref.…”

Massless Dirac fermions in III-V semiconductor quantum wells

“…Our experimental data clearly evidence a gapless state. We also measure cyclotron resonance (CR) at different electron concentrations varied by bipolar persistent photoconductivity (PPC) inherent to InAs-based QWs [27][28][29][30][31][32][33][34]. The latter acts as an optical gating and allows changing the electron concentration in the QW by several times.…”